Battery pack system

ABSTRACT

A source of environmental pollution is the burning of fuel by the transportation vehicles (e.g., cars, trucks). The use of electric vehicles (EVs) is perceived as an essential step towards better utilization of energy. Current EVs make use of an electric engine and a battery pack that provides energy to that engine. The technology of electric engines is well developed because of the common use of such engines in trains, submarines and industrial facilities. But, while the battery packs used in EVs have made a lot of progress in the last couple of years, these battery packs still have problems. These battery packs are expansive, heavy, and limited in the amount of energy that they can provide. This obstacle is a major factor that limits the use of EVs today in the mass market. Described herein is an improved EV battery pack system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/453,661, filed on Mar. 17, 2011 and also claims thebenefit of U.S. Provisional Patent Application No. 61/504,459, filed onJul. 5, 2011. The entirety of each of said provisional applications isincorporated by reference herein.

TECHNICAL FIELD

This disclosure relates to the field of battery pack systems. In someembodiments, it relates to electric vehicle (EV) battery pack systemsand also EV power train systems.

BACKGROUND

An EV battery pack typically includes several battery modules, eachcomprised out of several batteries (e.g., several single cellbatteries), that are packed into a hardened package. The specificationof the battery pack is determined by the car manufacturer and takes intoconsideration the extreme needs of the engine and the expectedenvironmental conditions. Thus the specification usually calls for extrabattery modules and/or for extra material, such as electrolyte, to beadded to the cells to compensate for production faults and degradationof the batteries over time. Additionally, EV battery packs have a fixedcurrent and voltage output.

Because electric engines need high current in order to produce hightorque and high voltage to produce high speed, the engine's demands fromthe battery pack change over time as the car goes from a state of highacceleration to a high speed state.

SUMMARY

Described herein is an improved battery pack system In one aspect, theimproved battery pack system includes battery pack that includes aswitching grid coupled to a controller. In some embodiments, theswitching grid includes a plurality of battery modules and a wiringstructure that enables the controller to change the configuration of thebatteries (e.g., cells) within the battery module and/or battery pack.This switching grid is used to change the output of the battery pack tofit the engine's current needs. The improved battery pack may beconfigured to take into consideration the concurrent state of eachbattery in the battery pack and environmental condition as well as thebattery history information and the manufacturer recommendations.

In one particular aspect, a switcher chip for use in interconnecting aset of cells is provided. In some embodiments, the switcher chipincludes: a main negative terminal; a cascading negative terminal; amain positive terminal; a cascading positive terminal; a plurality ofcell terminals; and a plurality of switches.

The switcher chip may be configured such that: (a) when a set of cellsare connected to the switcher chip via the plurality of cell terminalsand a first subset of the plurality of switches are closed and theremainder of the switches are open, the set of cells are connected inparallel with each other and current is able to flow out the mainpositive terminal but is not able to flow out the cascading positiveterminal, (b) when a set of cells are connected to the switcher chip viathe plurality of cell terminals and a second subset of the plurality ofswitches are closed and the remainder of the switches are open, the setof cells are connected in series with each other and current is able toflow out the main positive terminal but is not able to flow out thecascading positive terminal, (c) when a set of cells are connected tothe switcher chip via the plurality of cell terminals and a third subsetof the plurality of switches are closed and the remainder of theswitches are open, at least two of the cells in the set of cells areconnected in series with each other and current is able to flow out thecascading positive terminal but is not able to flow out the mainpositive terminal, (d) when a set of cells are connected to the switcherchip via the plurality of cell terminals and a fourth subset of theplurality of switches are closed and the remainder of the switches areopen, a subset set of cells are connected in parallel with each other,at least one cell is electrically disconnected from each of the othercells, and current is able to flow out the main positive terminal but isnot able to flow out the cascading positive terminal, and (e) when a setof cells are connected to the switcher chip via the plurality of cellterminals and a fifth subset of the plurality of switches are closed andthe remainder of the switches are open, a subset set of cells areconnected in series with each other and at least one cell from the setis electrically disconnected from each of the other cells of the set.

In some embodiments, switcher chip further includes a communicationcircuit comprising a transmitter and receiver, wherein the receiver iscommunicatively connected to either a controller or a transmitter of anadjacent switcher chip such that the receiver is operable to receiveswitching commands transmitted from either the controller or thetransmitter of the adjacent switcher chip.

In some embodiments, the switcher further includes a command decoderconfigured to error check commands received by the communication circuitfrom the controller or from another switcher chip and configured toblock erroneous commands.

In some embodiments, the switcher further includes switching controllogic connected to the command decoder and configured to convertcommands received by the communication circuit from the controller intoswitch on-off commands for switching elements within the battery module.

In some embodiments, the switcher further includes a safety switchingsequencer configured to receive the on-off commands from the switchingcontrol logic and configured to turn on or off at exact sequence andtime one or more of the switches based on the received on-off commands.

In some embodiments, the switcher further includes a slave inputterminal; a master output terminal; a slave communication module block;a master communication module block; a command decoder block; aswitching control logic block; and a safety switching sequencer block.

In some embodiments, the plurality of switches comprises a plurality ofpower metal-oxide semiconductor field effect transistors (MOSFETs).

In another aspect, a battery module is provided. In some embodiments,the battery module includes: a switcher chip comprising: a plurality ofswitches, a main positive terminal, a main negative terminal, acascading positive terminal and a cascading negative terminal; and a setof cells, the set of cells comprising: (i) a first cell having apositive terminal and a negative terminal, the positive terminal beingconnected to a first cell terminal of the switcher chip and the negativeterminal being connected to a second cell terminal of the switcher chip,and (ii) a second cell having a positive terminal and a negativeterminal, the positive terminal is connected to a third cell terminal ofthe switcher chip and the negative terminal is connected to a fourthcell terminal of the switcher chip, wherein the switcher chip isoperable to: (i) configure the switches such that (a) the cells areconnected in series, (b) current is able to flow out of the switcherchip via the main positive terminal but is not able to flow out theswitcher chip via the cascading positive terminal, and (c) current isable to flow into the switcher chip via the main negative terminal butis not able to flow into the switcher chip via the cascading negativeterminal, (ii) configure the switches such that (a) the cells areconnected in series, (b) current is able to flow out of the switcherchip via the cascading positive terminal but is not able to flow out theswitcher chip via the main positive terminal, and (c) current is able toflow into the switcher chip via the cascading negative terminal but isnot able to flow into the switcher chip via the main negative terminal,and (iii) configure the switches such that (a) the cells are connectedin parallel, (b) current is able to flow out of the switcher chip viathe main positive terminal but is not able to flow out the switcher chipvia the cascading positive terminal, and (c) current is able to flowinto the switcher chip via the main negative terminal but is not able toflow into the switcher chip via the cascading negative terminal.

In some embodiments, the switcher chip further comprises: acommunication circuit for receiving switching commands transmitted froma controller. In some embodiments, the switcher chip further comprises:a command decoder configured to error check commands received by thecommunication circuit from the controller or from another switcher chipand configured to block erroneous commands. In some embodiments, theswitcher chip further comprises: switching control logic connected tothe command decoder and configured to convert commands received by thecommunication circuit from the controller into switch on-off commandsfor switching elements within the battery module. In some embodiments,the switcher chip further comprises: a safety switching sequencerconfigured to receive the on-off commands from the switching controllogic and configured to turn on or off at exact sequence and time one ormore of the switches based on the received on-off commands.

In some embodiments, the first cell is a micro-cell and the second cellis a micro-cell. In some embodiments, the switcher chip controls lessthan seventeen single cell batteries but more than three single cellbatteries. In some embodiments, the switcher chip controls more than 7single cell batteries and less than 13 single cell batteries.

In another aspect, a battery pack system is provided. In someembodiments, the battery pack system includes a battery pack thatincludes: a first cluster of battery modules comprising a first columnof battery modules and a second column of battery modules; a firstcircuit for connecting the first column of battery modules in parallelwith the second column of battery modules; a second circuit forconnecting the first column of battery modules in series with the secondcolumn of battery modules; a second cluster of battery modulescomprising a third column of battery modules and a fourth column ofbattery modules; a third circuit for connecting the third column ofbattery modules in parallel with the fourth column of battery modules; afourth circuit for connecting the third column of battery modules inseries with the fourth column of battery modules, wherein at least oneof the battery modules in the first column has (i) a switch forconnecting and disconnecting a main output of the battery module to thefirst circuit and (ii) a switch for connecting and disconnecting acascading output of the battery module to the second circuit, at leastone of the battery modules in the second column has (i) a switch forconnecting and disconnecting a main output of the battery module to thefirst circuit and (ii) a switch for connecting and disconnecting acascading output of the battery module to the second circuit, at leastone of the battery modules in the third column has (i) a switch forconnecting and disconnecting a main output of the battery module to thethird circuit and (ii) a switch for connecting and disconnecting acascading output of the battery module to the fourth circuit, and atleast one of the battery modules in the fourth column has (i) a switchfor connecting and disconnecting a main output of the battery module tothe third circuit and (ii) a switch for connecting and disconnecting acascading output of the battery module to the fourth circuit.

In some embodiments, the battery pack system further includes acontroller for controlling the battery pack. The controller may beoperable to: (a) place the battery pack in a first mode of operation inwhich the battery pack produces a voltage V1; and (b) place the batterypack in second mode of operation in which the battery pack produces avoltage V2, where V2>V1. V2 may be greater than or equal to (n)(3.6)V1,where n is greater than or equal to 1. In some embodiments, at least oneof the battery modules comprises: a switcher chip comprising: aplurality of switches, a main positive terminal, a main negativeterminal, a cascading positive terminal and a cascading negativeterminal; and a set of cells comprising (i) a first cell having apositive terminal and a negative terminal, the positive terminal beingconnected to a first cell terminal of the switcher chip and the negativeterminal being connected to a second cell terminal of the switcher chip,and (ii) a second cell having a positive terminal and a negativeterminal, the positive terminal is connected to a third cell terminal ofthe switcher chip and the negative terminal is connected to a fourthcell terminal of the switcher chip.

In some embodiments, the controller is operable to: (i) cause thebattery module to configure the switches such that (a) the cells areconnected in series, (b) current is able to flow out of the switcherchip via the main positive terminal but is not able to flow out theswitcher chip via the cascading positive terminal, and (c) current isable to flow into the switcher chip via the main negative terminal butis not able to flow into the switcher chip via the cascading negativeterminal, (ii) cause the battery module to configure the switches suchthat (a) the cells are connected in series, (b) current is able to flowout of the switcher chip via the cascading positive terminal but is notable to flow out the switcher chip via the main positive terminal, and(c) current is able to flow into the switcher chip via the cascadingnegative terminal but is not able to flow into the switcher chip via themain negative terminal, and (iii) cause the battery module to configurethe switches such that (a) the cells are connected in parallel, (b)current is able to flow out of the switcher chip via the main positiveterminal but is not able to flow out the switcher chip via the cascadingpositive terminal, and (c) current is able to flow into the switcherchip via the main negative terminal but is not able to flow into theswitcher chip via the cascading negative terminal.

Other features are described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example battery pack system according to someembodiments.

FIG. 2 illustrates further illustrates an example battery pack systemand shows it being used in an vehicle having an electronic motor.

FIG. 3 illustrates an example battery pack according to someembodiments.

FIGS. 4-8 illustrate an example battery module according to someembodiments.

FIG. 9 illustrates another example battery pack according to someembodiments.

FIG. 10 illustrates another example battery module, according to someembodiments, that is based on a special dedicated chip.

FIG. 11 is a functional block diagram of a main controller according tosome embodiments.

FIG. 12 illustrates an environment in which a battery pack systemaccording to some embodiments may be used.

FIG. 13 illustrates a battery module according to another embodiment.

FIG. 14 illustrate a battery module according to still anotherembodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Conventional battery pack systems comprise a moderate numbers ofbatteries and a number of controllers, each of which monitors a group ofthe batteries (e.g., 10 of the batteries) for safety reasons mostly.Such a controller senses the voltage, temperature, and current of eachbattery in the group and, during the regular operation of the batterypack, levels the amount of charge in each battery by dischargingbatteries that are overcharged. In the case of an emergency (e.g., whenthe temperature or voltage of a certain cell reaches a predefinedvalue), the controller sends a signals to an aggregator controller thatthan shuts off a main power switch to disconnect the battery pack fromthe electric engine. This mechanism is fine for the sake of safety butdoes not apply to the other parameters needed from the battery pack.

It is well known in the industry that the nominal voltage of a cell isdetermined by the cell chemistry which is the electrochemical parametersof the chemicals used for the production. But when used, the actualvoltage on the cell terminals changes over time and depends of variousparameters that affect the internal impedance of the cells, like theambient temperature, the state of charge of the cells, the age of thecell, as well as the actual load current.

In the case of EV batteries packs, the use of Li-ion is the most commonand the nominal voltage value of each cell is 3.6V. Electric engines arecommonly used in many transportation vehicles like trains andsubmarines, these engines are very efficient and produce gradable powerdepending on the voltage and current provided to them. The voltage andcurrent range is in the order of hundreds, the voltage affects therotation speed of the motor while the current determines the Torque. Thepower of the motor in horse power is positive proportional to themultiplication of the rotation speed by the Torque.

In order to reach the range of hundreds of volts, tens of cells areconnected in series and then tens of chains are connected in parallel tosupport the peak current provisioning Since the cells are manufacturedin a relatively large capacity, if a certain cell is malfunctioning theeffect on the whole battery pack performance is significant. Moreover,because the battery pack structure is fixed and predefined, thismalfunctioning cell cannot be electrically excluded from the batterypack structure even though its impact on the power performance of thebattery can be negative.

This adds to the fact that the battery parameters are changing over timeand with regards to the environmental and use conditions and since thestructure is predetermined and fixed in the production process it needsto be compensated by additional material in the cells that are connectedin a non optimal fixed configuration. In practice, this fact leads theEV battery manufacturers to assign more than 60% more capacity in thebattery pack design and manufacturing to overcome the discussed problems

Referring now to FIG. 1, FIG. 1 is a diagram illustrating a battery packsystem 100, according to some embodiments, which overcomes at least someof the deficiencies of conventional battery pack systems.

As shown in FIG. 1, battery pack system 100 includes a battery pack 104,which includes (i) several batteries 101 (e.g., several single cellbatteries—which we shall refer to as a “cell”) and (ii) a batteryswitching grid 102 (a.k.a., “3D Battery Switching Grid™”302) thatenables the connection of the cells 101 in various different modes. Insome embodiments, the 3D Battery Switching Grid includes a plurality oflow cost chips (a.k.a., “switcher chips”), each of which is responsiblefor configuring a particular subset of the cells of the battery pack andeach of which contains a set of switches connected to the particularsubset of cells and circuit logic for controlling the switches. Batterypack system 100 may further include a main controller 106 (a.k.a., EVProcessor™) that monitors the state of each cell by its sensing thecell's specific parameters (e.g., state of charge, voltage, current,temperature, pressure etc.) and controls the switching grid based on, atleast in part, the current needs of the engine and the sensedparameters. The controller may also take into account the usage historyof the cells, the manufacturer motor behavior diagrams, and driverhistory and desires. Accordingly, battery pack system 100 enables moreefficient power utilization of the cells, increases safety, and providesthe best suited power source for different motors and for the currentneeds of that motor based on the driver's behavior and directions andthe driving environment. In some embodiments, the EV Processorincorporated within battery pack 104.

In some embodiments, as shown in FIG. 1, the battery pack system 100includes a number of cells that are each monitored separately and can beelectrically interconnected in various modes (e.g., parallel, serial orany other structure) during the usage by the car engine and during thecharge time. This way in which the cells are electrically interconnectedmay be changed periodically by the EV Processor to best match the actualneeds of the car (e.g., if high torque is needed the battery system canbe configured to provide a maximum amount of current. The specificconfiguration of each cell is determined by its current status, itshistory and the current task being performed as well as environmentalconditions.

For example, if the battery pack system 100 needs to perform in lowtemperature conditions more cells can be connected in series tocompensate for the degraded voltage contribution of each cell. Thismethod is also applicable for compensating of degradation in time. Asanother example, if a certain cell is malfunctioning, the malfunctioningcell may be electrically excluded from the battery pack structure andthe negative effect of its fault will be prevented.

In some embodiments, the cells may be relatively small (e.g., the cellsmay have a relatively small capacity—such as 2 Ah v. 20 Ah, forexample), in which case they may be referred to as micro-cells. With theuse of micro-cells management tasks can be done at adequate granularityand the battery manufacturer can design the battery in a much moreoptimal manner and can than reach higher power capacity and betterperformance over time for the same weight and volume. Another advantageof using micro-cells is that because they are smaller they can be usedmore cycles and the heat dissipation from them is better.

An EV battery pack is a fairly large object that consumes significantcar space and weight. There is a tradeoff in the design of a batterypack between energy capacity, space and weight—for the sake of moreenergy you would want to enlarge the battery pack, but this cost a lotin expensive material, space consumed in the car and additional carweight. Conventional battery packs are designed for providing themaximum voltage and current needed for the electric engine used and theenergy capacity needed between charges and for the sake of the batterylifetime.

Since most EV battery packs today are made using Li-ion battery cellsthe cells need to be monitored for overheating and over charging or elsea cell might explode. A battery cell that reaches 4.2 v or a designatedtemperature given by the manufacturer is considered dangerous andprovokes shut down of the main battery switch immediately causing thecar to stand aside. This mode of operation is essential to the abilityof using Li-ion in cars.

An improvement on conventional battery pack design is to add a switchinggrid (a.k.a., 3D Battery Switching Grid™) that will be comprised ofmultiple instantiations of a single low cost chip that enablescontroller 106 to manage each cell in the battery pack separately.Referring now to FIG. 2, FIG. 2 illustrates the 3D Switching Gridconcept. As illustrated in FIG. 2, battery pack 104 includes not only acollection of cells 101, but also a collection of switches 202. Asfurther illustrated in the embodiment shown in FIG. 2, at least twoswitches are present for each cell 101. In the example shown, switch 202a and switch 202 b are used to either (1) connect cell 101 a in serieswith other cells or (2) electrically disconnect cell 101 a from all theother cells. Thus, each cell in battery pack 104 can be electricallyincluded in the batter pack or electrically excluded from the batterypack.

The switching grid enables creating a structure that provides highervoltage, higher peak current or different cell order. It enables tocharge the cells in different order and to use part or all of the cellsin different utilization cases and by that optimizing the wear-out ofthe battery over the years. It will also enable to employ a safer usemethod because of the ability to temporarily or permanently electricallyexclude malfunctioning cells from the pack 104 in an early stage of aproblematic situation without the need to switch off the whole batteryand stop the car.

Referring now to FIG. 3, FIG. 3 illustrates an example structure ofbattery pack 104 according to some embodiments. As shown in FIG. 3, theexample battery pack 104 includes two clusters of battery modules 301.The first cluster (cluster 1) is made of two sets (or “columns”) of Mbattery modules (col. 1 a and col. 1 b) and a cascade wire 585 that isused to connect col. 1 a and col. 1 b in series. Likewise, the secondcluster (cluster 2) is made of two sets (or “columns”) of M batterymodules (col. 2 a and col. 2 b) and a cascade wire that is used toconnect col. 2 a and col. 2 b in series. In the example shown in FIG. 3,M=3. In some embodiments, battery module 301 includes a set of cells(e.g., 4 cells, 8 cells, or some other number of cells) and a componentof the switching grid 102 (e.g., one of the switcher chips mentionedabove that contain a set of switches).

Depending on how switches within battery modules 301 a and 301 b areconfigured, col. 1 a will either be in parallel with col. 1 b or theywill be in series. Likewise, depending on how switches within batterymodules 301 c and 301 d are configured, col. 2 a will either be inparallel with col. 2 b or they will be in series. Thus, for eachcluster, the columns of the cluster may be connected in parallel or inseries. However, in the embodiment shown, no column of cluster 1 can beconnected in series with a column of cluster 2. Accordingly, batterypack 104 may have at least two modes of operation: in one mode thecolumns in each cluster are connected in parallel and in another thecolumns in each cluster are connected in series. It is not required,however, that all columns in a cluster be connected in series orparallel. For example, with a cluster having four columns, the clustermay be configured such that columns 1 and 2 are in series therebyforming a first meta-column and columns 3 and 4 are in series therebyforming a second meta-column and the first meta-column is in parallelwith the second meta-column. As described further herein, there may beyet additional modes of operation because each battery module 301 can beconfigured such that it produces Va volts or Vb volts depending onwhether the cells of the battery module are connected in series orparallel. If each battery module produces Vi volts (e.g., Va or Vb) andthe all the columns of each cluster are connected in parallel, then thebattery pack 104 produces MxVi volts. However, if each battery moduleproduces Vi volts and the columns within each cluster are connected inseries, then the battery pack 104 produces BxMxVa volts, where B is thenumber of columns in the cluster. As described herein, a main controllermay configured battery pack 104 based on, for example, data regardingthe needs of the engine and/or the environment. Thus, if the enginerequires a high voltage, the main controller could send one or morecommands to the battery pack that cause the battery pack to connect thecolumns within each cluster in series and/or the cells within eachbattery module in series. Likewise, if the engine requires a high peakcurrent, the main controller could send one or more commands to thebattery pack that cause the battery pack to connect the columns withineach cluster in parallel and/or the cells within each battery module inparallel.

In the above structure, if one or several battery modules within thecolumn are malfunctioning, then the influence of these battery moduleson the whole pack can be trimmed by using switches within the batterymodule to bypass the battery modules temporarily or permanently. Anotheradvantage of the above structure is that the energy capacity redundancydesigned by the manufacturer can be spread wisely within the pack andcan be utilized to provide more current or more voltage according to theactual needs of the engine in any given time.

Referring now to FIGS. 4-8, FIGS. 4-8 illustrate an example batterymodule 301, which includes four batteries c1, c2, c3, c4 (e.g., fourmicro-cells), a set of switches (s0 through s14), a main positiveterminal 402, a main negative terminal 404, a cascading positiveterminal 582, and a cascading negative terminal 581. For simplicity, weshall refer to the batteries c1-c4 as cells with the understanding thatthe batteries are not limited to single-cell devices.

Switches s1-s4, s6-s8 and s10-s13 are used for interconnecting cellsc1-c4, while switches s0, s5, s9 and s14 are used for cascading columnsin a cluster. That is, switches s0, s5, s9 and s14 enable the batterymodule to connect in series with another battery module in a neighboringcolumn of the same cluster. For instance, terminals 581 and 582 are eachconnected to a respective cascade wire. The other end of the cascadewire is connected to a corresponding cascade terminal in a batterymodule that is positioned in an adjacent column. For instance, as shownin FIG. 3, terminal 581 of module 301 a is connected to wire 585 and theother end of the wire is connected to terminal 582 of module 301 b. Toconnect col. 1 a in series with col. 1 b, then (A) module 301 a isconfigured such that the following switches are closed s4-s8 and theothers are open and (B) module 301 b is configured such that thefollowing switches are closed s6-s10 and the others are open

As illustrated in FIGS. 4-8, a battery module (components of which maybe formed on a single chip) according to various embodiments of theinvention is capable of switching C cells that can be connected inserial, parallel or excluded from the grid. For example, a batterymodule is capable of electrically connecting C cells in parallel or inseries. As another example, for each one of the C cells, the batterymodule can electrically disconnect the cell from all of the other cellsin the battery module. Accordingly, a battery module has responsibilityfor C cells of the battery pack.

Thus, if one or several cells within the module are malfunctioning, thenthe influence of these cells on the whole pack can be trimmed by usingthe switches within the battery module to bypass the cells temporarilyor permanently. Another advantage of the above structure is that theenergy capacity redundancy designed by the manufacturer can be spreadwisely within the pack and can be utilized to provide more current ormore voltage according to the actual needs of the engine in any giventime.

As mentioned above, components of battery module 301 may be implementedas an integrated circuit or “microchip” (“chip” for short). That is, insome embodiments, battery module 301 comprises a chip and a set of cellsconnected to the chip. The chip is responsible for configuring the setof cells. For example, the chip is responsible for connecting the cellseither in series with each other or in parallel with each other. Thechip may include digital, analog and communication components. The chipmay make use of a noise-resilient communication module that decreasespossible control errors to the automotive levels needed as well asprevents unauthorized designers to make use of the module. In someembodiments, the chip uses Power FET technology for the switchingelements enabling very low Rds-on that leads to low self powerdissipation needed for energy efficiency. The chip may also include asafety switching sequencer that manages the exact switching sequence andtime of an individual cell to prevent hazardous situations. In someembodiments, the chip may include a small CPU and software code that inaddition to taking actions in response to commands received from acontroller can also act like a controller for certain tasks and react tospecific localized situations and take autonomic specific actions suchas, for instance, immediately switching-out a certain cell, or severalsells, that the chip senses is malfunctioning.

The switching elements need to support switching time that relates tothe application using the battery. In the case of an EV car, theswitching time needed is relatively slow and do not pose significantneeds from the switching elements, for instance the Power MOSFETmentioned

The constellations in which the switching elements are arranged withinthe battery module determines the level of flexibility when building thebattery switching grid. It is preferable to keep the number of switchingelements per battery module as low as possible in order to be able todesign a cost effective solution. Moreover, it is also preferable thateach of the switching elements need to bear only 1×I and thus can berelatively small. The connection that aggregate the currents fromseveral cells is done outside the chip of the battery module and utilizeseveral terminals of the chip.

FIG. 5 shows the battery module being configured such that all of thecells of the module are connected in parallel with each other. That is,c1 is parallel with c2, which is parallel with c3, which is parallelwith c4. This is accomplished by closing switches s1-s4 and s10-s13 andkeeping the others open. FIG. 6 shows the battery module beingconfigured so that cell c1 is excluded from the parallel circuit. Thisis accomplished by closing switches s2-s4 and s11-s13 and keeping theother switches open.

FIG. 7 shows the battery module being configured such that all of thecells of the module are connected in series. That is, c1 is in serieswith c2, which is in series with c3, which is in series with c4. This isaccomplished by closing switches s4, s6-s8, s10 and keeping the othersopen. In this configuration, current (i.e., conventional current) isable to flow out of main positive terminal 402 and current is able toflow into main negative terminal 404. If cascading is desired, thenswitches s5 and s9 are closed and switches s4 and s10 are opened. Inthis cascading configuration, a current is able to flow into cascadingnegative terminal 581 and then through cells c1-c4 and then outcascading positive terminal 582. FIG. 8 shows the battery module beingconfigured so that cell c1 is excluded from the series circuit. This isaccomplished by closing switches s4, s7, s8, s11 and keeping the othersopen.

As is illustrated in FIGS. 6 and 8, the switches are connected in a waythat enables to still make use of most of the other cells while theproblematic one is fully excluded from the module. Preferably, theswitches (e.g., Power FETs) have a very high switch-off impedance thusenable to safely exclude cells that are malfunctioning without the needto activate a main switch 1210 (see FIG. 2 or FIG. 12) and causing thecar to stop.

Since electric engines need high current in order to produce high torqueand high voltage to produce high speed, the needs from the battery arechanging from the start of movement of the car that needs high currentto the state when the car needs to increase the speed and the engineneed high voltage. The common range of the voltage needed is 48 to 800volts and the current changes between several to 300 Amperes. Thisconfiguration enables a dynamic power range of 1:C, where C is thenumber of cells handled by each battery module, meaning it can drive Ctimes the basic current or C times the basic voltage or any in between.

As described above, in the example battery module 301 shown in FIG. 4,which module is responsible for four cells (c1-c4), switches areconnected in a way that enables the battery module to connect the cellsin parallel or series connection. Moreover, as discussed above, otherswitches enable the cascading of columns within structure to supportmuch higher battery voltages. This structure benefits a high level offlexibility while still maintaining relatively low number of switchesand simple routing structure. The above configuration is unique alsobecause the aggregation of the current from each of the branches is donein the wiring outside of the battery module, enabling each Power FET tobe designed to transfer only 1×I current, keeping the area of the chipas small as possible and enables the lowest cost.

Referring now to FIG. 13, FIG. 13 illustrates a configuration of batterymodule 301 according to another embodiment. In this example, three cellsare shown for the sake of simplicity. In this embodiment, switches s1-s8and s10-s12 are used for interconnecting cells c1-c4, while switches s9and s13 are used for cascading columns in a cluster. In this embodiment,each cell can individually be disconnected from the other cells when themodule is in the series arrangement. For example, if the cells areconnected in series and then it is determined that cell c2 is bad, c2can be disconnected by opening switch s8 and closing switch s11.

Referring now to FIGS. 14 a, 14 b, and 14 c, these figures show anembodiment of battery module 301 that is similar to the embodiment shownin FIG. 3. One difference is that there are no middle cells and thecells that are used have higher current capacity than the cells used inthe embodiment shown in FIG. 3. This embodiment illustrates that thesame chip used in the battery module shown in FIG. 3 can be re-used toimplement other configurations.

Referring back to FIG. 3, while FIG. 3 shows that the example batterypack includes only two clusters, a batter pack according to otherembodiments may have more clusters. Likewise, while FIG. 3 shows thatthe example battery pack includes only two columns per cluster and threebattery modules 301 per column, other embodiments may have otherconfigurations.

For example, FIG. 9 shows an embodiment of battery pack 104 thatincludes N clusters of battery modules, where each cluster includes Bcolumns of battery modules, where each column includes M batterymodules, for a total of N×B×M battery modules. Each battery pack can bedesigned with different parameters of C, M, B and N, thus best matchingthe need of the specific car or manufacturing line. In one arrangement,each cluster is connected in parallel with each other cluster. For eachcluster, the columns of the cluster may be connected in parallel or inseries. For each column, the battery modules of the column are capableof being connected in series.

An advantage of this structure is the ability to limit the current thatis passing through each Power FET within the battery module to 1×I,where I is the maximum current supported in the specific design. Thismeans that in any configuration of the switching controls of the batterymodule the aggregation of the current is done by the special wiringstructure outside of the battery module itself, enabling a costeffective solution. Currently we found out that a cost-effectiveconstellation is built out of switchers with C=4 to 16. More preferably,in some applications, C ranges between 8 and 12.

The implementation of many parallel structures enables the use ofrelatively small Power FET that can be designated to small current andvoltage with lower Rds-on resistance, thus dissipates a smaller amountof power and become energy efficient.

Specifically, this structure enable the connection of C×B×N cells inparallel providing maximum current of I×(C×B×N) to be drown out of allthe cells and with the change of controls it enables the connection ofC×M×B cells in series, reaching V×(C×M×B) volts. The cascading of thecolumns within each cluster is enabled by the arrangement of switchesthat are used to interconnect the battery modules (see FIG. 3). Thisability to draw high current and reach very high voltage enables themanufacturer of the car to reach better care performance without thelimitations of fixed battery structure and is the outcome of theconstellation of the switching elements within the battery moduletogether with the specific routing design of the 3D Battery SwitchingGrid™ outside the battery module.

FIG. 10 is a block diagram of an example battery module 301 according tosome embodiments. In this embodiment, the battery module 301 includes(a) a chip 1002 containing switches and control circuitry and (b) amodule of cells 1004 (in this example the module of cells includes fourcells, other configurations are possible, such as 8 cells, which hasbeen found to be a cost effective number of cells). The example chip1002 shown in FIG. 10 is comprised of an analog and a digital part. Theanalog part is built out of Power MOSFETs that are arranged in thespecial constellation as described above. On one embodiment the numberof switches (e.g., Power MOSFETs) is 3+3*8=27.

These analog switches are controlled by the digital part of chip 1002that is comprised of several blocks: a communication module that iscapable of receiving switching commands from the EVProcessor™ in anerror-resilient fashion to meet the car safety standards. This module isbuilt out of a master (e.g., transmitter) and a slave (e.g., receiver)to enable a serial transfer of commands between one battery module tothe other and by that minimize the number of wires transferring theswitching commands within the battery pack. In some embodiments, theslave communication unit of a switcher chip 1002 (i) receives switchinginformation from the master communication unit of an upstream switcherchip 1002, (ii) selects the switching information that is addressed toit, and (iii) transfers to the next chip in the communication chaintrough the master communication unit the remainder of the switchinginformation that it received from the upstream chip. In this manner wesave on the number of wires that runs in the battery for transferringthe switching commands. That is, for example, the battery modules may beconfigured in a daisy chain arrangement where one of the battery modulesis configured to receive switching information from an outsidecontroller and then pass some, none or all of that switching informationto the next battery module in the communication chain, which module thendoes the same thing for the next battery module in the chain, etc.

A command decoder checks the received command to eliminate possiblefunctional errors that might create improper switching situation withinthe battery module or on a larger scale in the module or pack andtranslates the command for the switching control logic.

The switching control logic breaks the switching orders into actualon-off orders for each of the switching elements within the batterymodule.

The safety switching sequencer receives the on-off commands for each ofthe switches and determines the exact sequence and timing in which eachof the Power FETs needs to be switched. It takes into consideration thespeed of the switching element, energy consumption during the switchingsequence and of curse safety reasons—not to short any of the cells orcreate even momentarily an imbalance structure within the module orpack.

The EVProcessor™ 106—Sophisticated Powerful Controller

The idea of using many small battery cells is incorporated with the useof a special powerful chip that can handle efficiently theimplementation of the switching scheme according to the currently neededtask and usage method.

FIG. 11 is a functional block diagram of such proposed EVProcessor™ 106.

The EVProcessor™ is based on a processing device that can runsophisticated algorithms and make use of various different acceleratorsthat optimally match the computational tasks needed in order to utilizethe EV battery efficiently by the electric engine and to enable morelongevity and safety.

The EVProcessor™ implements control and “wear-out” algorithms enablingto manage each of the cells within the battery modules. This innovativeway of managing the battery cells will increase the energy efficiency ofthe battery enabling longer car distance drive and decrease the cost ofthe battery. The solution will also increase the safety usage of thebattery by disconnecting malfunctioning individual cells from the packwithout the need to stop the car and will decrease the type-2 errors of“faulty state of charge” from the same reason.

The EVProcessor™ runs two separate SW models: SmartLoad™ is an elementwhich manages individual cells at all conditions and significantlyimproves battery pack performance and DynamicPower™ is a vehicle-systemfed component that is designed to deliver voltage and current conditionsmatching the current specific engine needs in optimum fashion to theEV's inverter 1202 (see FIG. 12).

While SmartLoad™ is a standalone battery system booster that outsmartsexisting EV batteries by handling cells individually, rather than thebattery pack as a whole, DynamicPower™ requires integration withcarmakers and presents, beyond energy savings, an increased drivingperformance with simplified and cheaper inverter 1202.

The EVProcessor™ can sense the battery cells by means of analog ordigital inputs, it can manage the cells switching grid (i.e., theswitches within pack 104) using the digital outputs, it can connect toadditional devices trough the scalability port, it can make use of itsinternal memory and Flash to hold the battery history and statistics foreach cell and can extend this DB to an external memory. It can alsoconnect to external engines through its specific bus and can communicatewith the car main controller or other devices by means of wired orwireless connections to manage battery storage for instance.

The ability to change the structure of the battery on-the-fly and in adynamic manner that best matches the environmental and engine changingneeds and that can compensate different time degradation effects andmalfunctions of part of the cells redefines the battery specificationand largely affect the ability to use it in different scenarios withchanging parameters and environments especially cover for temperaturechanges.

FIG. 12 illustrates an example EV power train system 1200 that includesan embodiment of battery pack system 100 described herein. As shown,system 1200 includes a motor 1204 connected to an inverter 1202 that iselectrically connected to the output terminals of battery pack 104,thereby receiving current output from battery pack 104. System 1200 alsoincludes a main controller 1206 and a bus 1208 that allows thecomponents to communicate. For example, EVProcessor™ can use bus toobtain data from main controller and to provide commands to batterymodules 301 within battery pack 104. The EVProcessor™ can also resideinside the battery pack 104 or as part of the main controller 1206 inthe form of control-software and algorithms.

Examples

1. A Cell is Producing Lower Voltage than the Rated Voltage

Because of the chemical structure a certain cell within the battery packcan become defected, let's say because of production fault and producesless than the rated voltage. In the current structure of the batterypack this cell will continue to appear in the serial structure of thechain and the outcome will be that the voltage that is produced out ofthe battery is constantly reduced by that amount. Over time, more andmore cells are producing less voltage and the battery output voltage isdropped significantly.

To overcome this problem the manufacturer is using additional sparecells in series that leads to higher voltage than the actual needed andis than dropped within the system.

With the systems described herein, for a certain interval of time, theEVProcessor™ reads the current engine speed, determines the bestappropriate voltage for that speed, and calculates the number of seriescells needed to supply the best appropriate voltage. This can be done byutilizing the engine manufacturing information that specifies the bestappropriate voltage per each speed. It than reads a cell historydatabase and reviews the amount of usage cycles of each cell. Theprocessor also read the current voltage of each cell and decides for thecoming period of time which of the cells will be used and how many cellswill be connected in serial and in parallel.

In some embodiments, the use of many micro-cells instead of large cellsenables the processor to control the battery voltage in fine granularityand if a certain cell is malfunctioning and kept aside the overalleffect on the battery capacity is negligible.

The outcome of this periodically continues process is that the voltagethat the battery produces can be kept constant over time and overcomethe hurdle of loss of voltage because of wear-out of certain batterycells within the chain.

The battery manufacturer can than specify less redundant cells withinthe battery structure because it can use less serial constantlyconnected cells and this additional cells can support the parallelstructure instead to provide for the needed peak current.

2. Voltage Drop Because of Environmental Temperature

It is well known that batteries are producing less voltage if theambient temperature drops significantly. To overcome this problem themanufacturers are specifying additional series cells that in regularambient temperature are than producing excessive voltage than needed andis than dropped within the system.

With the systems described herein, for a certain interval of time, theEVProcessor™ reads the current engine speed and calculates the amount ofseries cells needed to supply the best appropriate voltage. It thanreads the cell history database and review the amount of usage cycles ofeach cell. The processor also read the actual voltage of each cell thatis with respect to the current ambient temperature and decides for thecoming period of time which of the cells will be used and how many cellswill be connected in serial and in parallel.

3. Efficient Battery Charging

In the case of such large batteries that are comprised of many cells,that need to perform well over a long period of time, say 5 years inLi-ion car batteries, the charging task is becoming critical for thelifetime of the battery and the safety of the user. The current constantstructure of the battery poses a process of charge that involves all thebattery cells at once. This process of charging can be harmful if acertain cell is overcharged and for that there is a safety levelingmechanism that discharges the cells to a certain voltage, keeping allthe cells in a predefined voltage range.

With the systems described herein, for a certain charge interval oftime, the EVProcessor™ reads the actual voltage of each cell and thecell history database to review the amount of charge cycles the cellhave already passed. It than decides for the coming period of chargetime which of the cells will be charged and how many cells will beconnected in serial and in parallel in order to create the best chargecurrent flow. Cells that reach the maximum voltage allowed are keptaside while other cells charge continues. This enables charge of all ofthe cells to their maximum capacity. In this manner the full capacity ofthe battery can be used.

The outcome of this charge process is that cells that don't need to becharged are kept out of the charging chain and are not worn-out byunnecessary charges. These cells are also less exposed to over-chargesituation thus the battery usage is much safer. The overall charge timecan be reduced in the factor of N because of charging more cells inparallel and even utilize charge in lower charge current per cell,extending the life cycle of the battery. The battery manufacturer canthen specify less cells within the battery structure because it can useless serial constantly connected cells that overcome the ware-outproblem and this additional cells can support the parallel structureinstead to provide for the needed peak current.

4. Efficient Battery Discharging

In the case of such large batteries that are comprised of many cells,that need to perform well over a long period of time, say 5 years inLi-ion car batteries, the discharging task is becoming critical for thelifetime of the battery. The Li-ion chemistry limits the charging of thecells to 2.5V minimum. Discharging the battery to lower rate will createirreversible damage to the cell and will disable the use of the holepack. The current constant structure of the battery poses a process ofdischarge that involves all the battery cells at once. This process ofdischarging can be harmful if a certain cell is over discharged and forthat reason there is a mechanism that stops the discharge of the entirepack if even only one of the cells reaches 2.5V. This mechanism disablesthe utilization of the full capacity of each of the cells and limits itby the weakest cell in the pack. It is well known that after only 200cycles the battery pack will have significant cell to cell variationsand this create inefficient utilization of the battery capacity.

With the systems described herein, for a certain charge interval oftime, the EVProcessor™ reads the actual voltage of each cell. It thendecides for the coming period of charge time which of the cells will bedischarged and how many cells will be connected in serial and inparallel in order to create the best discharge current flow. Cells thatreach the minimum voltage of 2.5V allowed are kept aside (i.e.,electrically disconnected as described above) while other cellsdischarge continues. This enables the discharge of all of the cells totheir minimum capacity. In this manner the full capacity of the batterycan be used.

The outcome of this discharge process is that cells that finished thedischarge cycle are kept out of the discharge chain and are not limitingthe ability to continue the discharge of the rest of the cells. Thesecells are also less exposed to over-discharge situation thus the batteryusage is much gentle, extending the life cycle of the battery. Thebattery manufacturer can then specify fewer cells within the batterystructure because it can use less constantly connected cells thatovercome the ware-out problem reducing the overall cost of the battery.

5. Optimized EV Motor performance

In the case of such large battery packs that are comprised of manycells, that need to perform well over a long period of time, providingthe best values of current/voltage according to the constantly changingneeds of the motor is a challenging task. The current constant structureof the battery poses the manufacturer to assemble the battery pack in astructure that will have enough cells in parallel connection to supportthe highest current needed for needed torque performance and in the sametime to assemble enough cell in serial to support that highest voltageneeded to support the horse power needs. This design process is limitedby the weight and cost of the battery pack and forces the manufacturerto compromise on the car performance values.

With the systems described herein, for a certain interval of time, theEVProcessor™ reads the car manufacturer engine graph that is stored inthe database and the actual voltage of each cell and as well as the cellhistory database to review the amount of charge cycles the cell havealready passed. It than decides for the coming period of time which ofthe cells will be used and how many cells will be connected in serialand in parallel in order to create the best structure to support theneeded motor voltage and current. This way of using the cells in aflexible structure give the manufacturer a new degree of freedom in thedesign of the battery structure and support better motor values oftorque and horse power providing a better car to the customer for thesame battery cost.

The battery manufacturer can also specify fewer cells within the batterystructure because it can use different cell structure to support theextreme current or voltage needs in different period of time.

This advance use of the battery power is saving a lot of energy,complexity and cost invested today into the structure of the inverterthat needs to support the demanding AC needs of the motor from a fixedDC battery power. The EVProcessor™ can replace most of the functionalityof the Inverter by creating the desired AC power by constantly changingthe amount of serial cells connected together to create the momentarilyvoltage.

Other Battery Uses

Even though the primary goal of this invention is to better utilizeElectric Vehicles Battery packs, battery pack system 100 can be used fordifferent battery applications like mobile phones or laptop computers.Of course, the economy of each use-case is different but the basicpractice in which we divide the battery to cells, connect them with the3D Battery Switching Grid™ battery switching grid and employsophisticated micro-management and control methods can be matched toevery case.

1. A switcher chip for use in interconnecting a set of cells,comprising: a main negative terminal; a cascading negative terminal; amain positive terminal; a cascading positive terminal; a plurality ofcell terminals; and a plurality of switches, wherein the switcher chipis configured such that: when a set of cells are connected to theswitcher chip via the plurality of cell terminals and a first subset ofthe plurality of switches are closed and the remainder of the switchesare open, the set of cells are connected in parallel with each other andcurrent is able to flow out the main positive terminal but is not ableto flow out the cascading positive terminal, when a set of cells areconnected to the switcher chip via the plurality of cell terminals and asecond subset of the plurality of switches are closed and the remainderof the switches are open, the set of cells are connected in series witheach other and current is able to flow out the main positive terminalbut is not able to flow out the cascading positive terminal, when a setof cells are connected to the switcher chip via the plurality of cellterminals and a third subset of the plurality of switches are closed andthe remainder of the switches are open, at least two of the cells in theset of cells are connected in series with each other and current is ableto flow out the cascading positive terminal but is not able to flow outthe main positive terminal, when a set of cells are connected to theswitcher chip via the plurality of cell terminals and a fourth subset ofthe plurality of switches are closed and the remainder of the switchesare open, a subset set of cells are connected in parallel with eachother, at least one cell is electrically disconnected from each of theother cells, and current is able to flow out the main positive terminalbut is not able to flow out the cascading positive terminal, and when aset of cells are connected to the switcher chip via the plurality ofcell terminals and a fifth subset of the plurality of switches areclosed and the remainder of the switches are open, a subset set of cellsare connected in series with each other and at least one cell from theset is electrically disconnected from each of the other cells of theset.
 2. The switcher chip of claim 1, further comprising: acommunication circuit comprising a transmitter and receiver, wherein thereceiver is communicatively connected to either a controller or atransmitter of an adjacent switcher chip such that the receiver isoperable to receive switching commands transmitted from either thecontroller or the transmitter of the adjacent switcher chip.
 3. Theswitcher chip of claim 2, further comprising: a command decoderconfigured to error check commands received by the communication circuitfrom the controller or from another switcher chip and configured toblock erroneous commands.
 4. The switcher chip of claim 3, furthercomprising: switching control logic connected to the command decoder andconfigured to convert commands received by the communication circuitfrom the controller into switch on-off commands for switching elementswithin the battery module.
 5. The switcher chip of claim 4, furthercomprising: a safety switching sequencer configured to receive theon-off commands from the switching control logic and configured to turnon or off at exact sequence and time one or more of the switches basedon the received on-off commands.
 6. The switcher chip of claim 1,further comprising: a slave input terminal; a master output terminal; aslave communication module block; a master communication module block; acommand decoder block; a switching control logic block; a safetyswitching sequencer block.
 7. The switcher chip of claim 1, wherein theplurality of switches comprises a plurality of power metal-oxidesemiconductor field effect transistors (MOSFETs).
 8. A battery module,comprising: a switcher chip comprising: a plurality of switches, a mainpositive terminal, a main negative terminal, a cascading positiveterminal and a cascading negative terminal; and a set of cells, the setof cells comprising: (i) a first cell having a positive terminal and anegative terminal, the positive terminal being connected to a first cellterminal of the switcher chip and the negative terminal being connectedto a second cell terminal of the switcher chip, and (ii) a second cellhaving a positive terminal and a negative terminal, the positiveterminal is connected to a third cell terminal of the switcher chip andthe negative terminal is connected to a fourth cell terminal of theswitcher chip, wherein the switcher chip is operable to: (i) configurethe switches such that (a) the cells are connected in series, (b)current is able to flow out of the switcher chip via the main positiveterminal but is not able to flow out the switcher chip via the cascadingpositive terminal, and (c) current is able to flow into the switcherchip via the main negative terminal but is not able to flow into theswitcher chip via the cascading negative terminal, (ii) configure theswitches such that (a) the cells are connected in series, (b) current isable to flow out of the switcher chip via the cascading positiveterminal but is not able to flow out the switcher chip via the mainpositive terminal, and (c) current is able to flow into the switcherchip via the cascading negative terminal but is not able to flow intothe switcher chip via the main negative terminal, and (iii) configurethe switches such that (a) the cells are connected in parallel, (b)current is able to flow out of the switcher chip via the main positiveterminal but is not able to flow out the switcher chip via the cascadingpositive terminal, and (c) current is able to flow into the switcherchip via the main negative terminal but is not able to flow into theswitcher chip via the cascading negative terminal.
 9. The battery moduleof claim 8, wherein the switcher chip further comprises: a communicationcircuit for receiving switching commands transmitted from a controller.10. The battery module of claim 9, wherein the switcher chip furthercomprises: a command decoder configured to error check commands receivedby the communication circuit from the controller or from anotherswitcher chip and configured to block erroneous commands.
 11. Thebattery module of claim 10, wherein the switcher chip further comprises:switching control logic connected to the command decoder and configuredto convert commands received by the communication circuit from thecontroller into switch on-off commands for switching elements within thebattery module.
 12. The battery module of claim 11, wherein the switcherchip further comprises: a safety switching sequencer configured toreceive the on-off commands from the switching control logic andconfigured to turn on or off at exact sequence and time one or more ofthe switches based on the received on-off commands.
 13. The batterymodule of claim 8, wherein the first cell is a micro-cell and the secondcell is a micro-cell.
 14. The battery module of claim 8, wherein theswitcher chip controls less than seventeen single cell batteries butmore than three single cell batteries.
 15. The battery module of claim8, wherein the switcher chip controls more than 7 single cell batteriesand less than 13 single cell batteries.
 16. A battery pack systemcomprising a battery pack, the battery pack comprising: a first clusterof battery modules comprising a first column of battery modules and asecond column of battery modules; a first circuit for connecting thefirst column of battery modules in parallel with the second column ofbattery modules; a second circuit for connecting the first column ofbattery modules in series with the second column of battery modules; asecond cluster of battery modules comprising a third column of batterymodules and a fourth column of battery modules; a third circuit forconnecting the third column of battery modules in parallel with thefourth column of battery modules; a fourth circuit for connecting thethird column of battery modules in series with the fourth column ofbattery modules, wherein at least one of the battery modules in thefirst column has (i) a switch for connecting and disconnecting a mainoutput of the battery module to the first circuit and (ii) a switch forconnecting and disconnecting a cascading output of the battery module tothe second circuit, at least one of the battery modules in the secondcolumn has (i) a switch for connecting and disconnecting a main outputof the battery module to the first circuit and (ii) a switch forconnecting and disconnecting a cascading output of the battery module tothe second circuit, at least one of the battery modules in the thirdcolumn has (i) a switch for connecting and disconnecting a main outputof the battery module to the third circuit and (ii) a switch forconnecting and disconnecting a cascading output of the battery module tothe fourth circuit, and at least one of the battery modules in thefourth column has (i) a switch for connecting and disconnecting a mainoutput of the battery module to the third circuit and (ii) a switch forconnecting and disconnecting a cascading output of the battery module tothe fourth circuit.
 17. The battery pack system of claim 16, furthercomprising a controller for controlling the battery pack.
 18. Thebattery pack system of claim 17, wherein the controller is operable to:(a) place the battery pack in a first mode of operation in which thebattery pack produces a voltage V1; and (b) place the battery pack insecond mode of operation in which the battery pack produces a voltageV2, where V2>V1.
 19. The battery pack system of claim 18, wherein V2 isgreater than or equal to n3.6V1, where n is greater than or equal to 1.20. The battery pack system of claim 18, wherein at least one of thebattery modules comprises: a switcher chip comprising: a plurality ofswitches, a main positive terminal, a main negative terminal, acascading positive terminal and a cascading negative terminal; and a setof cells comprising (i) a first cell having a positive terminal and anegative terminal, the positive terminal being connected to a first cellterminal of the switcher chip and the negative terminal being connectedto a second cell terminal of the switcher chip, and (ii) a second cellhaving a positive terminal and a negative terminal, the positiveterminal is connected to a third cell terminal of the switcher chip andthe negative terminal is connected to a fourth cell terminal of theswitcher chip.
 21. The battery pack system of claim 20, wherein thecontroller is operable to: (i) cause the battery module to configure theswitches such that (a) the cells are connected in series, (b) current isable to flow out of the switcher chip via the main positive terminal butis not able to flow out the switcher chip via the cascading positiveterminal, and (c) current is able to flow into the switcher chip via themain negative terminal but is not able to flow into the switcher chipvia the cascading negative terminal, (ii) cause the battery module toconfigure the switches such that (a) the cells are connected in series,(b) current is able to flow out of the switcher chip via the cascadingpositive terminal but is not able to flow out the switcher chip via themain positive terminal, and (c) current is able to flow into theswitcher chip via the cascading negative terminal but is not able toflow into the switcher chip via the main negative terminal, and (iii)cause the battery module to configure the switches such that (a) thecells are connected in parallel, (b) current is able to flow out of theswitcher chip via the main positive terminal but is not able to flow outthe switcher chip via the cascading positive terminal, and (c) currentis able to flow into the switcher chip via the main negative terminalbut is not able to flow into the switcher chip via the cascadingnegative terminal.